Purchase Blooio numbers

Purchase one or more Blooio lines. Purchases are asynchronous and billable: the call charges the organization's default payment method and returns a purchase_id; the lines are provisioned when Stripe confirms the invoice, at which point a number.purchase.completed webhook fires (or number.purchase.failed). A card requiring 3DS/SCA returns status: action_required with an action_url, and also emits number.purchase.action_required. Idempotency is required — send a unique Idempotency-Key header; replaying the same key returns the same purchase rather than charging twice. Rules enforced server-side (identically to the dashboard): the organization must have a saved payment method (else 402 no_payment_method); shared plans are limited to one line per organization (409 shared_number_limit); and a single order may not exceed the per-order line cap (400 line_limit_exceeded, default 10 — apply for an increase in the dashboard Limits tab). Requested area codes that are out of stock incur a custom area-code fee and open a provisioning ticket; in-stock codes are assigned immediately with no custom fee. Requires the number purchase API feature to be enabled, and the numbers:manage scope for OAuth apps.